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Speciation and Reproductive Isolation in General Biology

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  • What is speciation?

    Speciation is the evolutionary process by which populations evolve to become distinct species.
  • Define biological species concept.

    A biological species is a group of populations whose members can interbreed and produce fertile offspring.
  • What is reproductive isolation?

    Reproductive isolation prevents different species from interbreeding and producing fertile offspring.
  • What are hybrids?

    Hybrids are offspring resulting from the mating of individuals from two different species or populations.
  • List the five prezygotic barriers.

    Prezygotic barriers include habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation.
  • What are postzygotic barriers? Name three types.

    Postzygotic barriers occur after fertilization and include reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown.
  • What is a hybrid zone?

    A hybrid zone is a geographic area where interbreeding occurs between two species, producing hybrids.
  • Explain reinforcement in speciation.

    Reinforcement strengthens reproductive barriers to prevent hybrid formation and maintain species integrity.
  • Compare macroevolution and microevolution.

    Microevolution involves small genetic changes within a population; macroevolution refers to large-scale evolutionary changes that create new species.
  • Contrast prezygotic and postzygotic barriers.

    Prezygotic barriers prevent mating or fertilization; postzygotic barriers reduce viability or fertility of hybrids after fertilization.
  • Define allopatric speciation.

    Allopatric speciation occurs when populations are geographically separated, leading to reproductive isolation.
  • Define sympatric speciation.

    Sympatric speciation occurs without geographic separation, often through genetic or behavioral changes within a population.
  • Give an example of allopatric speciation.

    Shrimp and fruit flies are examples where geographic isolation led to allopatric speciation.
  • What role does habitat isolation play in speciation?

    Habitat isolation prevents species from encountering each other, reducing gene flow and promoting speciation.
  • Describe temporal isolation.

    Temporal isolation occurs when species breed at different times or seasons, preventing mating.
  • What is behavioral isolation?

    Behavioral isolation involves differences in mating behaviors that prevent interbreeding.
  • Explain mechanical isolation.

    Mechanical isolation occurs when physical differences prevent successful mating between species.
  • What is gametic isolation?

    Gametic isolation happens when sperm and egg of different species cannot fuse to form a zygote.
  • What is reduced hybrid viability?

    Reduced hybrid viability means hybrids fail to develop properly or survive to reproductive age.
  • What is reduced hybrid fertility?

    Reduced hybrid fertility means hybrids are sterile or have low fertility, preventing gene flow.
  • Define hybrid breakdown.

    Hybrid breakdown occurs when offspring of hybrids have reduced viability or fertility in subsequent generations.